The present disclosure relates to a system for measuring and assessing hemodynamics in an anatomical structure of a subject, and a method for image processing hemodynamics in at least a part of an anatomical structure in video images acquired from a subject. In particular the present disclosure relates to measuring and assessing hemodynamics in, around and near the surface, in particular the gastrointestinal wall, of the gastrointestinal tract of a subject.
Complications related to the gastrointestinal tract are often related to local hemodynamics. I.e. a change in the normal hemodynamic conditions may be an indicator of a complication. Perfusion assessment of the gastrointestinal tract, in particular in and near the surface of the gastrointestinal tract, such as the tissue of the gastrointestinal wall, can therefore be an important diagnostic tool when examining the gastrointestinal tract, e.g. for diagnosis or for localization of a complication, for example during diagnostic laparoscopy, explorative laparoscopy or surgical laparoscopy with traditional laparoscopy or robotic surgery, as well as in open surgery. Perfusion assessment is also important during the surgical procedure of anastomosis which can be provided to establish communication between two formerly distant portions of the gastrointestinal tract. As an example intestinal anastomosis establishes communication between two formerly distant portions of the intestine and typically restores intestinal continuity after removal of a pathologic condition affecting the bowel. Intestinal anastomosis may for example be provided for 1) restoration of intestinal, such as bowel, continuity following resection of diseased intestine, and 2) bypass of unresectable diseased intestine, e.g. bowel. Certain pediatric conditions may also require intestinal anastomosis [6].
Resection of diseased bowel can be performed in the following settings:                Bowel gangrene due to vascular compromise caused by mesenteric vascular disease, prolonged intestinal obstruction, intussusceptions, or volvulus        Malignancy        Benign conditions (e.g. intestinal polyps, intussusception, roundworm infestation with intestinal obstruction)        Infections (e.g. tuberculosis complicated with stricture or perforation)        Traumatic perforations        Large perforations (traumatic) not amenable to primary closure        Radiation enteritis complicated with bleeding, stricture, or perforation        Inflammatory bowel disease, ulcerative colitis, or Crohn's disease that is refractory to medical therapy or associated with complications (e.g. bleeding, perforation, toxic megacolon, dysplasia/carcinoma)        Chronic constipation, idiopathic slow transit constipation, or Hirschsprung's disease: Subtotal colectomy may be performed when the disease is refractory to medical therapy.        
Bypass of unresectable diseased bowel can be performed in the following settings:                Locally advanced tumor causing luminal obstruction        Metastatic disease causing intestinal obstruction        Poor general condition or condition that prevents major resection        
Pediatric conditions for which intestinal anastomosis may be required include the following:                Congenital anomalies (e.g. Meckel diverticulum, intestinal atresia, malrotation with volvulus leading to gangrene, meconium ileus, duplication cysts, Hirschsprung's disease)        Inflammatory conditions (e.g. necrotizing enteritis, enterocolitis, tuberculosis, enteric perforation)        Other conditions (e.g. intussusception, angiodysplasia, polypoid disease, ascariasis)        As a part of other surgical procedures (e.g. Kasai portoenterostomy, choledochal cyst, urinary diversions, pancreatic neoplasms)        
Postsurgical complications in connection with anastomosis in the gastrointestinal tract are unfortunately frequent, often due to insufficient perfusion (capillary blood supply) at the anastomosis, i.e. the joining of the two parts of the tract. Insufficient perfusion may cause anastomotic leakage, which is a serious and frequent complication, for example in connection with colorectal surgery where more than 10% of the procedures result in complications. Within colon cancer surgery more than 30% of patients with anastomotic leakage die due to postoperative complications and approx. 25% of the remaining patients suffer from stoma for the rest of their lives. Risk factors associated with leakage include tension of anastomosis, tissue damage and in particular reduced blood perfusion.